WO2021074069A1

WO2021074069A1 - Glazing unit mounted on a structure by fastening points, at least one of which is play-free with respect to the glazing unit or to a gripping frame thereof

Info

Publication number: WO2021074069A1
Application number: PCT/EP2020/078588
Authority: WO
Inventors: Jean-Benoît MAYEUX; Flavien Fremy
Original assignee: Saint-Gobain Glass France
Priority date: 2019-10-14
Filing date: 2020-10-12
Publication date: 2021-04-22
Also published as: FR3101849A1; BR112022005310A2; FR3101849B1; IL292076A; EP4045396A1; CN114521182A; KR20220079610A; CA3152092A1

Abstract

The subject of the invention is: - a monolithic or laminated glazing unit (1), which is bolted or gripped by a frame (4) that is itself bolted onto or through a structure (3), characterized in that, in at least one part of the periphery of the glazing exhibiting maximum flexibility or minimum stiffness with regard to the phenomenon of buckling, said bolting is realized by means of at least one bolt (2) inserted into a bushing (7) concentric with the bolt (2), or replaced by the insertion of a bushing (7) or of a pin (7), each bushing (7) or each pin (7) being mounted without play on the glazing unit (1) or on the frame (4), and on or through the structure (3); - the application of this glazing unit (1) as aviation glazing.

Description

Title: Glazing mounted on a structure by fixing points, at least one of which is free of play with respect to the glazing or to a clamping frame thereof

The invention relates to the field of bolted glazing for vehicles (land, water or air) subjected to pressures (static or dynamic) which may present a risk of buckling. A static pressure here refers to a pressure exerted on the outer face of the glazing of an aircraft, for example, at a constant non-zero speed, and a dynamic pressure at a pressure exerted on the outer face of the glazing of an aircraft whose speed varies. Buckling is defined as an inversion of curvature of the glazing, generally towards the interior (or the cabin) of the airplane under the effect of a load such as aerodynamic pressure. The aerodynamic pressures from the outside to the inside being low, less than 0.1 bar, compared to the cabin pressurization level greater than 0.6 bar, the buckling phenomenon does not concern the glazing of pressurized aircraft.

Currently, the glazing is bolted directly or by means of a glazing clamping frame, on or through the assembly structure (aircraft cabin, etc.) so as to keep the glazing integral with it . The screws support the glazing against the structure. The fixing points can be numerous, for example a number greater than 80 for a glazing of 1.2 m ² : this requires mounting the screws with a clearance on the glazing or the clamping frame thereof, to that the holes in this glazing or in this frame are in front of the corresponding ones in the structure, for the bolts tightened last. The glazing is stopped in translation by friction (under the screw head), and the ball joint stresses the body of the screw itself.

To guard against the risk of buckling, the possibilities are to thicken the transparency and / or the frame to increase the stiffness of the glazing, and / or to multiply the number of fixing points to stiffen the boundary conditions.

These possibilities pose several problems, of varying importance depending on the areas (land / air), which are as follows:

- significant increase in weight: thickening the transparency and increasing the number of fixings directly impacts the weight of the glazing; this is particularly problematic in aeronautical applications;

- increase in assembly time: increasing the number of fasteners means longer and more expensive replacement time (in terms of time and components); moreover, multiplying the number of fixing points increases the complexity of the tightening (order) and the repeatability of the boundary conditions;

- weakening of the edge resistance: the holes are areas of high stress concentration; increasing the number of holes means increasing the stresses; in addition, a thicker (stiffer) transparency will transmit more stresses to the attachments in the event of an impact (bird, pedestrian, animal, projectile, etc.): the edge of the mounting structure and the edge of the glazing (frame) must be sized accordingly (heavier).

The invention consists in defining specific fixing points (rigid fixing), combining the traditional function of keeping the glazing resting on the structure with anti-translation and anti-translation functions. swiveling to locally stiffen the boundary conditions.

To this end, the invention relates to a monolithic or laminated glazing, bolted or clamped by a frame itself bolted on or through a structure, characterized in that in at least part of the periphery of the glazing of maximum flexibility or of minimum stiffness with respect to the buckling phenomenon, said bolting is carried out by means of at least one bolt inserted in a sleeve concentric with the bolt, or replaced by the insertion of a sleeve or a pin, each sleeve or each pin being mounted without play on the glazing or on the frame, and on or through the structure.

A monolithic glazing consists of a single transparent sheet of mineral glass such as soda-lime, aluminosilicate, borosilicate, etc., optionally thermally toughened or chemically reinforced, or of a polymer material such as poly (methyl methacrylate) (PMMA), polycarbonate (PC) , polyurethane (PU), ionomer resin ...

Laminated glazing is made up of several such transparent sheets of mineral glass or polymer material bonded two by two by an intermediate adhesive layer of polyvinyl butyral (PVB), thermoplastic polyurethane (TPU), ethylene vinyl acetate (EVA) ...

When a socket is employed, it is inserted without play into a corresponding hole in the glazing or the clamping frame thereof. The screw of a bolt concentric with the bushing can be inserted into it, or on the contrary, the bushing is independent of any screw, of any screw-nut assembly (bolt). The socket, like the pin, is also inserted without play into a corresponding hole in the mounting structure, possibly passing through the structure. The rigid fixing points (without clearance) are specially defined (quantity and position) according to the parameters of the use case (dimension / shape / thickness of the glazing, structure rigidity, pressure distribution, materials used, etc. ) to avoid any hyper-droop and maintain the product's mountability without constraints. The number of sockets and pins, the passage of a screw or not in a socket, the shapes of the sockets and pins used (seen in more detail below), the presence or not of a shoulder on the sleeves / pins, and the joint use of different bushings and / or pins will also be adapted according to these parameters of the case of use.

The rigid fixing points in accordance with the invention are advantageous for glazing subjected to pressures liable to cause buckling and the mass of which it is desired to limit and / or to facilitate implementation, assembly and / or replacement.

The invention makes it possible, by combining a few rigid fixing points in the less steep parts of the periphery of the glazing, where buckling is likely to arise, at known fixing points, with play, to reduce the total number of points. fixing the glazing without modifying its behavior with respect to buckling, or maintaining the total number of fixing points by reducing or eliminating buckling.

Preferably, said sleeve or said pin is made of a rigid, mechanically resistant material such as metallic or composite comprising reinforcing fillers and / or fibers.

Preferably, at least one sleeve has a cylindrical tube section geometry.

Preferably, at least one pin is cylindrical and solid. Preferably, at least one pin is conical and solid.

Preferably, at least one sleeve or at least one pin has a shoulder, in particular bearing and stopping against the surface of said structure.

Another object of the invention consists in the application of a glazing as described above, as glazing subjected to static or dynamic pressures, in particular as aeronautical glazing, in particular as aircraft or helicopter glazing.

The accompanying drawings illustrate the invention. The figures are schematic cross-sectional representations of glazing subjected to static and / or dynamic pressures, in particular of aircraft, mounted on a structure.

[Fig. 1] and [Fig. 2] represent known glazing at rest.

[Fig. 3] and [Fig. 4] show known glazing in the buckling position.

[Fig. 5] and [Fig. 6] represent a first known type of solution to the problem of buckling.

[Fig. 7] and [Fig. 8] represent a first type of embodiment according to the invention.

[Fig. 9] and [Fig. 10] represent a second type of embodiment in accordance with the invention.

Referring to Figure 1, an aircraft glazing 1 is clamped by a frame 4 bolted to a structure 3 (cabin) by means of a bolt 2 consisting of a screw and a nut. A washer 5 separates the screw head from the upper half of the frame 4 for clamping the glazing 1. A water and air seal 6 separates the lower half of the frame 4 and the structure 3.

In view of the large number of fixing points by bolting aircraft glazing 1, the screw of bolt 2 is inserted with play in the hole of the frame 4, so that the holes of the frame 4 coincide with the corresponding holes of the structure 3, until the end of the bolting, that is to say including for the bolts tightened in last place.

Figure 2 differs from Figure 1 by the absence of an intermediate frame 4, the glazing 1 being this time itself provided with a hole and bolted directly on and through the cabin 3. The screw of the bolt 2 is , for the same reasons as in Figure 1, inserted with play in the hole in glazing 1.

The glazing mounted in Figures 1, respectively 2, are shown in buckling condition, in Figures 3, respectively 4. The stop in translation is made by friction under the screw head of the frame 4, respectively of the glazing 1. The swiveling solicits the body of the screw itself.

To limit (reduce, eliminate) buckling, the mounted glazing units of Figures 1, respectively 2, can be modified by thickening them as shown in Figures 5, respectively 6. The resulting weight is obviously unfavorable, especially in an aeronautical application.

According to a first embodiment of the invention, the mounted glazing units of Figures 1, respectively 2, have one or more (not all, in general a minority, a limited number of) points of fixing by bolting modified as shown. in Figures 7, respectively 8. A socket 7 is inserted without any play into the hole of the frame 4 or of the glazing 1 on the one hand, of the cabin 3 on the other hand. The screw of a bolt 2 can be inserted into the socket 7 as shown in Figures 7 and 8, but it might as well not be. According to a second embodiment of the invention, the mounted glazing of Figures 1, respectively 2, have one or more (not all, in general a minority, a limited number of) points of fixing by bolting modified (s) as shown in Figures 9, respectively 10. A pin 7 (solid) cylindrical, respectively conical, is inserted without any play in the hole of the frame 4, respectively of the glazing 1. The latter is therefore conical.

The bush 7 of Figure 8 like the pin 7 of Figure 10 has a support and stop shoulder against the lower surface of the cabin 3.

According to the invention, the modification of a limited number of fixing points by bolting according to these Figures 7, 8, 9 and 10, in the parts of the periphery of the glazing of less rigidity, parts where the buckling originates, is sufficient. to reduce / eliminate buckling.

Claims

1. Monolithic or laminated glazing (1), bolted or clamped by a frame (4) itself bolted to or through a structure (3), characterized in that in at least part of the periphery of the glazing of maximum flexibility or of minimum stiffness vis-à-vis the buckling phenomenon, said bolting is carried out by means of at least one bolt (2) inserted in a sleeve (7) concentric with the bolt (2), or replaced by the insertion of 'a socket (7) or a pin (7), each sleeve (7) or each pin (7) being mounted without play on the glazing (1) or on the frame (4), and on or through the structure (3).

2. Glazing (1) according to claim 1, characterized in that said sleeve (7) or said pin (7) consists of a rigid mechanically resistant material such as metallic or composite comprising fillers and / or fibers. reinforcement.

3. Glazing (1) according to one of the preceding claims, characterized in that at least one sleeve (7) has a cylindrical tube section geometry.

4. Glazing (1) according to one of the preceding claims, characterized in that at least one pin (7) is cylindrical and solid.

5. Glazing (1) according to one of the preceding claims, characterized in that at least one pin (7) is conical and solid.

6. Glazing (1) according to one of the preceding claims, characterized in that at least one sleeve (7) or at least one pin (7) has a shoulder, in particular bearing and stopping against the surface of the structure. (3).

7. Application of a glazing (1) according to one of the preceding claims, as glazing subjected to static or dynamic pressures.

8. Application of a glazing (1) according to claim 7, as aeronautical glazing, in particular as aircraft or helicopter glazing.